J. F. Silva and G. P. Lopes, A Document Descriptor Extractor Based on Relevant Expressions, 14th Portuguese Conference on Artificial Intelligence, pp.646-657, 2009.
DOI : 10.1016/j.ipm.2007.01.015

J. M. Cigarrán, A. Peas, J. Gonzalo, and F. Verdejo, Automatic Selection of Noun Phrases as Document Descriptors in an FCA-Based Information Retrieval System, ICFCA 2005, Lecture Notes in Computer Science 3403, pp.49-63, 2005.
DOI : 10.1007/978-3-540-32262-7_4

F. Liu, D. Pennell, F. Liu, and Y. Liu, Unsupervised approaches for automatic keyword extraction using meeting transcripts, Proceedings of Human Language Technologies: The 2009 Annual Conference of the North American Chapter of the Association for Computational Linguistics on, NAACL '09, 2009.
DOI : 10.3115/1620754.1620845
URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.370.9534

A. Hulth, Enhancing linguistically oriented automatic keyword extraction, Proceedings of HLT-NAACL 2004: Short Papers on XX, HLT-NAACL '04, 2004.
DOI : 10.3115/1613984.1613989
URL : http://acl.ldc.upenn.edu/n/n04/n04-4005.pdf

R. Yangarber and R. Grishman, Machine Learning of Extraction Patterns from Unanotated Corpora: Position Statement. Workshop on Machine Learning for Information Extraction, Held in conjunction with the 14th European Conference on Artificial Intelligence (ECAI). 21 August, 2000.

J. Christian, Spotting and Discovering Terms through Natural Language Processing, 2001.

J. L. Martínez-fernández, A. García-serrano, P. Martínez, and J. Villena, Automatic Keyword Extraction for News Finder, Lectures Notes in Artificial Intelligence, vol.3094, pp.99-119, 2004.
DOI : 10.1007/978-3-540-25981-7_7

G. Ercan and I. Cicekli, Using lexical chains for keyword extraction In Information Processing and Management: an International Journal archive, 1705.

G. A. Miller, The science of words, Scientific American Library, 1991.

F. D. Silva and G. P. Lopes, Towards Automatic Building of Document Keywords, COLING 2010 -The 23rd International Conference on Computational Linguistics, 2010.

F. D. Silva, G. Dias, and S. Guilloré, Using LocalMaxs Algorithm for the Extraction of Contiguous and Non-contiguous Multiword Lexical Units, 9th Portuguese conference on artificial intelligence Evora, pp.21-24, 1999.
DOI : 10.1007/3-540-48159-1_9

B. S. Everitt, The Cambridge Dictionary of, Statistics, CUP, 2002.

F. Sebastiani, Machine learning in automated text categorization, ACM Computing Surveys, vol.34, issue.1, pp.1-47, 2002.
DOI : 10.1145/505282.505283
URL : http://arxiv.org/abs/cs/0110053